Field of the Invention
The present invention relates to a torque coupler having a variable spring constant.
Discussion of the Background
In the field of robotics, robots are needed that can operate efficiently and safely under a variety of conditions/environments. For example, in certain operational conditions in which there is minimal risk of the robot colliding with other items, the robot can operate using high speed without taking precautions for collisions. Alternatively, in certain operational conditions, for example in which the robot in collaboration with workers or other robots or in confined spaces, precautions much be taken in order to ensure the safety of the workers, and to prevent damage to the robot or other robots/structures.
In high speed operational conditions, it can be advantageous to a torque coupler that can act as a series elastic actuator (SEA) with a high stiffness value that can prevent oscillations from occurring during changes in acceleration of members of the robot. In certain operational conditions, such as in collaborative settings in which the robot is working with a worker, the use of an SEA with low stiffness values can improve the safety of the workers. Additionally, in certain operational conditions, such as in force control modes of operation, it can be advantageous to enable a robot controller to hold a specified position under variable process loads. Accordingly, there is a need for a torque coupler that can advantageously provide a variable spring constant within the SEA. Additionally, in certain operational conditions, such as in force control modes of operation, it can be advantageous for the torque coupler to monitor torque transmission. Additionally, in certain operational conditions, such as holding a specified position or path under variable process loads, it can be advantageous for the torque coupler to monitor deflection or twist.